SECT. 4] HEAT-PRODUCTION OF THE EMBRYO 655 



2-9 gm. cal., in the 5th hour 10-5, and in the nth hour 22-8. All 

 these figures, except the first one, are rather higher than the corre- 

 sponding ones of Meyerhof, though it must be remembered that 

 Shearer was working with Echinus miliaris and Meyerhof with 

 Strongylocentrotus lividus. In another experiment where 146-2 mgm. 

 Ggg nitrogen were present, 

 6-34 gm. cal. were given 

 oflfin the ist hour, 28-0 gm. 

 cal. in the 5th hour, and 

 74-4 in the nth hour. For 

 the ist hour following fer- 

 tilisation Shearer obtained 

 a calorific quotient of 3-22, 

 while for the unfertilised 

 Q:gg his average figure was 

 3-07. He did not wish, 

 however, to draw any con- 

 clusions from this diflfer- 

 ence, for, in view of the 

 large numbers of eggs which 

 had to be used in the case 

 of eggs before fertilisation, 

 and the inevitable indi- o 

 vidual differences between 

 females in ripeness, physio- 

 logical condition, etc., it 

 was perhaps wise not to 

 lay too great stress on the 

 variation between the unfertilised and fertilised eggs. Nevertheless, 

 the values obtained were much nearer the theoretical values than 

 those of Meyerhof, so that it was not unlikely that these more 

 accurate measurements had overcome the loss of heat which had 

 led to his low calorific quotients. As Fig. 117 shows, Shearer's 

 result worked out at about the level of protein combustion, although 

 he himself laid no stress at all upon this fact; and certainly it did 

 not agree very well with the respiratory quotient of 0-95 which he 

 obtained simultaneously on the same material. What seemed to him 

 of especial importance was that there was no marked difference 

 between the calorific quotient of unfertilised and of fertilised eggs, 



5 

 Fig. 118. 



10 



